ANN ARBOR, Mich. -- The teammates of Michigan defensive lineman Rashan Gary say they are growing frustrated with rumors that Gary is holding himself out of games with his NFL future in mind.

Gary, a potential first-round draft pick according to most draft experts, did not play for Michigan in the month of October while dealing with a shoulder injury. He missed games against Maryland, Wisconsin and Michigan State. Head coach Jim Harbaugh said Monday he didn't know if Gary would be healthy enough to play this Saturday against Penn State.

Carlo Kemp, a fellow defensive lineman for the Wolverines, said he can see his teammate's frustration with not being able to play. He said he's confident Gary will be back on the field as soon as he is physically able to be.

"He's just a hard worker, everything he does. Now he's attacking the rehab trying to get back," Kemp said Monday afternoon. "I know Rashan very, very closely. He's not a guy who is trying to take himself out of the game. He's always trying to get into the game. That's what he's doing."

Gary is one of several high-profile college football players who missed time during the second month of the season. Houston's Ed Oliver sat out this past week's game. Ohio State's Nick Bosa decided to withdraw from school and focus on preparing for the NFL several weeks after he had surgery to repair a muscle issue in his core.

Harbaugh said last week that he wasn't sure if Gary would return this season. When he was asked about Gary not making the trip to East Lansing for the team's annual rivalry game with Michigan State, the coach said: "Rashan didn't feel like he could play in the game."

Gary's mother, Jennifer Coney-Shepherd, said last week in a Facebook post that Gary originally injured his shoulder prior to the first game of the season and tried to play through it. After several weeks of playing, medical personnel told him he was at risk for needing surgery if he didn't take more time to heal properly.

"Why would people say he's quitting football because he has to heal?" she said. "My son is and always will be a warrior. My son is a Wolverine! He has pride in himself, his team (and) his academics (and) until Michigan plays their last game he will be part of (the) team. He will however not (participate) until he is fully recovered."